feat: replace YAML hosts editor with form-based CRUD table

Settings > Hosts now renders a table with per-column controls
(watch, dyndns, owner, managers/monitors multi-select, threshold
config, notification channels) instead of a raw YAML textarea.
Changes stage via the existing Publish flow like other form sections.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

tests/test_settings_sections.py

@@ -24,7 +24,7 @@ def test_sections_have_section_mode():
     sections = settings_mod.get_settings_sections(CFG)
     for s in sections:
         assert "section_mode" in s, f"Section {s['id']} missing section_mode"
-        assert s["section_mode"] in ("form", "yaml", "channels")
+        assert s["section_mode"] in ("form", "yaml", "channels", "hosts")
 
 
 def test_sections_have_api_section():
@@ -46,14 +46,20 @@ def test_yaml_sections_have_correct_mode():
     sections = settings_mod.get_settings_sections(CFG)
     yaml_sections = {s["id"]: s for s in sections if s["section_mode"] == "yaml"}
     assert "channels" not in yaml_sections  # now uses "channels" mode
-    assert "hosts" in yaml_sections
+    assert "hosts" not in yaml_sections     # now uses "hosts" mode
     assert "thresholds" in yaml_sections
     assert "dns" in yaml_sections
-    assert yaml_sections["hosts"]["api_section"] == "hosts"
     assert yaml_sections["thresholds"]["api_section"] == "thresholds"
     assert yaml_sections["dns"]["api_section"] == "dns"
 
 
+def test_hosts_section_uses_hosts_mode():
+    sections = settings_mod.get_settings_sections(CFG)
+    hosts_sec = next(s for s in sections if s["id"] == "hosts")
+    assert hosts_sec["section_mode"] == "hosts"
+    assert hosts_sec["api_section"] == "hosts"
+
+
 def test_channels_section_uses_channels_mode():
     sections = settings_mod.get_settings_sections(CFG)
     ch_sec = next(s for s in sections if s["id"] == "channels")